//英文常规字母分布频率
/*var letterFrequency = [8.4966, 2.0720, 4.5388, 3.3844, 11.1607, 2.26, 1.71,
	6.33, 7.10, 0.14, 0.41, 3.77, 2.26, 7.06,
	7.26, 2.00, 0.09, 6.10, 6.85, 9.41,
	2.58, 1.09, 1.59, 0.21, 1.58, 0.08];*/ //另外一个比例版本
var letterFrequency = [0.082, 0.015, 0.028, 0.042, 0.127,
	0.022, 0.02, 0.061, 0.07, 0.001,
	0.008, 0.04, 0.024, 0.067, 0.075,
	0.019, 0.001, 0.06, 0.063, 0.09,
	0.028, 0.01, 0.024, 0.02, 0.001, 0.001
];